Pyrrole → Sodium pyrrolide

Participants

Reaction Steps

Manipulations of all reactants were carried out either in a dry box employing nitrogen, or in airless glassware employing vacuum or nitrogen. Tetrahydrofuran (THF), toluene, benzene, diethylbenzene (Aldrich, 97% mixture of 1,2-, 1,3-, 1,4- isomers) and pentane were purified by distillation over sodium-benzophenone ketyl under nitrogen, then degassed via a nitrogen purge. Dimethoxyethane (DME) (Aldrich, anhydrous) was degassed via nitrogen purge and used without further purification. Pyrrole (Aldrich, 98%) was vacuum distilled over sodium, then degassed via nitrogen purge. 2,5-Dimethylpyrrole was dried with calcium sulfate and vacuum distilled. Sodium 2,5-dimethylpyrrolide (NaC6H8N) was prepared by reacting 2,5-dimethylpyrrole with an excess of sodium (40% by weight dispersion in mineral spirits) in refluxing tetrahydrofuran under nitrogen. Sodium pyrrolide was prepared by reacting pyrrole with an equivalent molar amount (1:1) of NaH (Aldrich, 60% by weight in mineral oil) or sodium (40% dispersion by weight in mineral spirits) in dimethoxyethane or tetrahydrofuran (THF) at ambient temperature under nitrogen. Triethylaluminum (TEA) (Aldrich 1.0M, hexanes and 1.9M toluene) was used as received. Ketjen Grade B alumina (Al2O3) and Davison 952 silica (SiO2) were the commercial materials used as supports for catalyst preparations. Fluorided-alumina (F/Al2O3, 15 wt % F) was prepared by the addition of a solution of NH4HF2 in ethanol to Ketjen Grade B alumina. Phosphated silica (P/SiO2, P/Si molar ratio=0.1) was prepared by the addition of a 10% H3PO4 /methanol solution to Davison 952 silica. The aluminophosphate (AlPO4) used in the following experiments was made as described in McDaniel at al, U.S. Pat. No. 4,364,855 (1982). The supports were activated by placing up to 25 g into a fritted quartz tube, fluidizing with air and calcining at 700° C., except for P/SiO2 at 350° C., for 3 hours. The air stream was switched to nitrogen until the support cooled to ambient temperature.

Provenance & Evidence